4.6L Modified "Low buck" stroker

[lafrad]

Well, got things rolling to rebuild the 4.0L in my 1999 Cherokee. It currently has 170K+ miles on it, and is getting noisy... in ways noise makes you uncomfortable. Also, I had an unfortunate run with some ice and a trailer that was moving slower than I was... Gotta pull everything apart and fix brackets, rad, grille, etc etc etc etc.

Goal is: its currently a winter driver/"work" truck... i have an '06 Dodge Charger for my daily driver. Not really worried about what octane fuel, the charger sucks down 91-93 octane do to an 11.5:1 cr 400ci motor... i do plan on slowly building it up for some fun off road, but that probably isn't in the scope of "this year"

So, general idea, so far, is going to be do this as cheap as I can, but don't cut a corner if value added is significant enough.

'99 block - will be out of jeep shortly.
4.2L short nose crank, Offset ground +0.022" (3.939" stroke... altered to get favorable quench without decking block) Bearings sized to match the offset grind.
4.2L rods.
"standard" head gasket. No need to chase down a thin one if I can get the piston to be zero deck. 0.050" quench is good enough.

0.030" oversize pistons : would like Hypereutectic with a significantly enlarged dish to get SCR reasonable.

Cam: <fill in the blank> Need to find one to play well with the SCR that the rotating assembly comes up with

Stock head: "cleanup" porting. lapped valves. New valve springs. replace anything that looks significantly worn. Maybe roller rockers.

Stock intake stuff - For now.
Stock exhaust stuff - For now.

I have a PSC piggyback that will be installed... (had it on the charger before tuning was available)

Anyone have any suggestions? advice to avoid? Changes of plans?

[lafrad]

Status report, parts incoming:

4.2L Offset Ground crank. 3.939 stroke (0.040" bearings, 0.022 offset)
Lunati VooDoo cam & lifter kit: http://www.lunatipower.com/Product.aspx?id=1476&gid=287
0.030" oversize Hypereutectic pistons: http://store.summitracing.com/partdetai ... STL-H802CP
Speedpro Moly rings: http://store.summitracing.com/partdetai ... -E-925K-30
Clevite Gaskets (0.041" MLS head gasket) http://www.coolparts.com/products/ENGIN ... 2-195.html

Still have some debate on the rods. Anyone use these: http://thejeep.com/shop/HARD+PARTS/ENGI ... +258+(4.2L).html
? They are apparently *NEW* aftermarket rods. basically drop them in and go.

As soon as pistons get here, will be sending them off for a little bit more dish volume (Thanks oletshot!). 20cc for them

once all that gets here it will be off to the machine shop. going to get the pistons to be 0.005-0.008 out of the hole, shooting for a .035" quench. (should be a very very very small skim off the deck with offset ground crank)

Then will add a bit more volume to the cyl head via a carbide tool and a bunch of patience

Still need to find valvesprigns and a header. Any suggestions there?

[lafrad]

Looks like I'll have a modification or three to the gasket kit... Will take pics of anything that doesn't match up.

[dwg86]

check www.pawinc.com for connecting rods. They advertise 258 rods resized, shot peened, arp rod bolts and balanced for $90.00.

[lafrad]

Just called and they won't give a casting number for the part.

I guess I'd take my chances on the new rods than end up with a set of 232 rods with ultra strong bolts.

[lafrad]

Ended up ordering a *new* set of aftermarket rods:
http://thejeep.com/shop/HARD+PARTS/ENGI ... +258+(4.2L).html

don't have to resize, don't have to put new bolts in, The price was worth it for me. Even if they turn out to be less than ideal, the engine will see very little time above 4500 rpm, so I'm not worried in the slightest.

I really wanted a lunati cam, but I couldn't get past the +0.500" lifts and having to do expensive work to the head for proper valve spring control.
So, I have a Crower "POWER COMPU-PRO / PERFORMANCE LEVEL 2" cam on the way. 256/264 advertised, 194/204 @ 0.050 @ 112 lsa. Gonna find an adjustable timing set and set it up 2-4 * retarded. Should be a decently torquy cam and still play decent with the 10:1 SCR I'll end up with. Also I got a smokin' hot deal on it, so it was hard to pass up.
http://crower.com/misc/m_cat.shtml

While I was at It I ordered a set of the cam saver lifters too. Just gotta become *not lazy* and get the pistons shipped out for a little work, and get my block back from the shop... and we are movin'

[gradon]

That's the 1st time I've looked at Crower's cams--they look like a good mfg. You'll be glad you got those pistons dished to keep the dcr down.

[lafrad]

I have a custom ground crower cam in my hemi and it seems to match up well (hasn't caused any trouble and runs real well).

I do have the "DCR" concerns, the cam really isn't that big... but it matches a stock-ish head, stock-ish valvetrain, and the desire for a 100% perfectly smooth Daily Driver that anyone could use. with 4* of retard on it it shouldn't sacrifice too much torque and bleed off enough pressure to keep it in the mid-grade area for fuel.

[lafrad]

She Lives!

After 2 nights of trying to figure out a no-start condition, (several dizzy installs, new coil, rotor, cap, wires, multi-meter, etc) she started right up! Ran just long enough between 2 and 3K to get the oil mixed up and around the system a time or two, and shut down. Need to install cooling fans before break-in.

The crower cam is VERY smooth...

I ended up with a Borla header & midpipe, Random Tech cat, and the stock '99 rust-back... so its quiet.

Should be street-worthy next week

[gradon]

good deal

[lafrad]

I'll hopefully be able to give impressions of the setup in a few days...

I'm just excited its running heh.

ya, and the mid 90's style borla header on the '99 intake manifold is PITA. took a bunch of work with a grinder on the intake and a few taps of a the hammer on the header to get decent clearance on one of the rear primaries....

[lafrad]

Cam break in and road test:
I saw no excessive "junk" in the initial fill of oil. lots of Zinc/Phos additives, and straight 30 weight conventional oil (with "normal" zddp levels) idled at 40 psi on the oil gauge when hot (heh)

Changed the filter (Motocraft FL-1A for all filter changes)... topped off the oil and put 25 miles on it, easy driving, no extended idle... really REALLY drove nice. NO cam lope, NO idle surge, and a GREAT feel like the jeep just lost 500 lbs. Acceleration is smooth and brisk, passing gear on the freeway is smooth an no longer labored... PERFECT. haven't gone WOT yet, no wideband and no tuning stuff hooked up yet... Still really high oil pressure, 40 psi at idle, 60-65 at freeway speeds & revving... BUT...

got an oil change: went to the instant oil change place and watched them do all the work. New filter, and they flushed 4 qts of 5W-20 through the motor (drain plug open, pump the oil through). Then, drain plug in, add a bottle of Lucas Break in treatment (ZDDP knock off) and then fill with 5.5 qts of 5W-30 valvolene, conventional oil.
Startup/warmup and engine oil pressure is down to 25-30 at idle, 45-50 at 2500 rpm. Perfect. Might be a little high for some of you, but I'm very happy with it. It'll switch to some Royal purple after a few thousand miles... and I'll fiddle with the viscosity to keep the oil pressure in the "good" range.


The valvetrain is SILENT! there is NO lifter noise, NO rocker noise, NO valve noise! The injectors and long tube headers are the loudest part of the whole thing! love it

[Bodo]

sweet! What did you get the pistons dished to?

[lafrad]

Pistons dished to ~20cc... the max that everyone says to go on the Hypereutectics....

[SilverXJ]

I would think that the Voodoo can would be a bit on the noisy side as it has the more aggressive ramp rates like the CompCam Xtreme cams do. Its interesting that it isn't though.